A generalization of the above lemma to arbitrary boundary conditions is given in .
For more information on these topics, we refer to [1]}.
To measure the jumps between \(i_{\omega }({\gamma })\) 
and \(i_\lambda ({\gamma })\)  with \(\lambda \in {\bf U}\)  near \({\omega }\)  from two sides of \({\omega }\)  in \({\bf U}\) , the splitting numbers \(S_M^{\pm }({\omega })\)  is defined by followings.
